Antiperspirant products typically use aluminum and zirconium-based salts as the active antiperspirant ingredient to control perspiration and malodor. However, such active antiperspirant ingredients can be perceived negatively by consumers due to health and environmental concerns. Moreover, the use of high concentrations of such active antiperspirant ingredients can cause irreversible staining of clothing.
The above issues have been addressed in a number of ways including the addition to an antiperspirant composition of a water soluble polymer comprising Brønsted acid groups. See, e.g., U.S. Pat. No. 6,616,921; U.S. Patent Application Publication No. 2005/0100521 A1; and International Publication No. WO 02/49590 A2. However, in the only issued patent, it is required that the water soluble polymers form true solutions in water, where a true solution typically has an absorbance of less than 0.2, preferably less than 0.1 (for a 1 cm path length at 600 nm).
Accordingly, there is a need for new antiperspirant/deodorant compositions that can reduce the high concentrations of conventional antiperspirant and deodorant ingredients while maintaining antiperspirant efficacy. In addition, there is a need for a new class of polymers that can be used in conjunction with lower concentrations of active antiperspirant ingredients in antiperspirant/deodorant compositions.